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Created page with '===Insect Body=== *Covered by an exoskeleton **Provides support and protection to the living tissues **Acellular so is secreted by underlying epidermis **The outer layer is cal…'
===Insect Body===
*Covered by an exoskeleton
**Provides support and protection to the living tissues
**Acellular so is secreted by underlying epidermis
**The outer layer is called the '''epicuticle''' which is composed of proteins and covered by a waxy layer
**The inner layers are the '''endocuticle''' and '''exocuticle''' which are composed of protein and chitin
*Body is '''metameric''' (divided into segments)
*Divided into head, body and abdomen
**Articular membranes link segments allowing movement
===Insect Head===
[[Image:Insect Head and eyes.jpg|thumb|right|150px|Alan Hadley]]
[[Image:Insect Eyes.jpg|thumb|right|150px|Alan Hadley]]
[[Image:Blow fly head.jpg|thumb|right|150px|Blowfly Head Close Up - Martin Pot - Wikimedia Commons]]
*Capsule of fused plates at the anterior end of the body
*One large pair of compound eyes
**Honeycomb like corneal facets
*Three simple ocelli
**Dorsal to compound eyes
*One pair of antennae
====Antennae====
*Form varies amongst insecta
**E.g. long and segmented, short and squat etc.
*[[Hair - Anatomy & Physiology|Hairs]] sometimes present
*Aristae (bristles) sometimes present
====Mouthparts====
*Modification depending on feeding method
*Insects which suck up liquified food have an expanded sponge like labellae
**Cannot penetrate skin
**Palps are also present which are sensory structures
*Insects which suck blood have long slender mouthparts for piercing skin
**Hypopharynx
**Mandibles
**Labrum
**Maxillae
*Larval mouthparts are prominent
**One pair of hooks
**Cephalo-pharyngeal skeleton
**Mouthparts help identify larvae
===Insect Thorax===
*Divided into three segments
**Prothorax, mesothorax and metathorax
*Each segment has one pair of legs attached
*One or two pairs of wings may be present on the mesothorax and metathorax
====Leg====
*Leg is attached to the body by '''coxa'''
*Trochanter
*Femur
*Tibia
*Tarsus, which is composed of several segments
*Claw
*Usually six-segmented
====Wing====
[[Image:Insect Wing Venation.jpg|thumb|right|150px|Alan Hadley]]
*Insects usually posess two pairs of wings
*Diptera have a reduced second pair of wings called '''halteres''' for balance
*Membranous outgrowth of the integument
*Strengthened by a network of veins comprising breathing tubes ([[Trachea - Anatomy & Physiology|trachea]]) and [[Vascular System - Anatomy & Physiology|blood vessels]]
*The wing venation can be used for identification
**Longitudinal veins
**Cross veins
**Open cells
**Closed cells
===Insect Abdomen===
*Segmented
*Soft
*Appendages present
**Copulatory claspers
**Ovipositor
**External genitalia
====Respiratory System====
*Branching [[Trachea - Anatomy & Physiology|trachea]] strengthened by spiral thickenings in the walls
*[[Trachea - Anatomy & Physiology|Trachea]] communicate with outside via spiracles
**Spiracles on side of body
**Chitinous openings
**Muscular control so can open and close at will
**Mounted on stigmatic plates
**Lead to trachea
*Muscular contactions of the body wall produce respiratory movements
*Shape of spiracles and stigmatic plates used for species identification
====Alimentary and Excretary System====
*The precise shape of the gut varies between [[:Category:Arthropods|arthropods]]
*The Alimentary canal is divided into fore, mid and hind gut
*Foregut:
**[[Oesophagus - Anatomy & Physiology|Oesophagus]]
**[[Crop- Anatomy and Physiology|Crop]] for temporary food storage
**[[The Proventriculus - Anatomy & Physiology|Proventriculus]]
**[[The Gizzard - Anamtomy & Physiology|Gizzard]] present in insects which eat solid food
***Muscular wall and teeth on inner surface
*Midgut:
**Stores food
**Secretes enzymes for digestion
**Outlet for malpighian tubules (equivalent of the mammalian kidney)
*Hindgut:
**Water resorption
====Circulatory System====
*[[Heart - Anatomy & Physiology|Heart]] situated dorsally
**Valves divide [[Heart - Anatomy & Physiology|heart]] into compartments
**Valves only let blood flow forwards
*[[The Aortic Arches - Anatomy & Physiology|Aorta]]
*Branching [[Vascular System - Anatomy & Physiology|blood vessels]]
*Haemocoele
**General body cavity
**Equivalent to the capillary circulation in mammals
**Contains haemolymph
*Ostia (openings) in the [[Vascular System - Anatomy & Physiology|blood vessel]] walls allow return of blood to the heart
====Nervous System====
*Small brain above the [[Oesophagus - Anatomy & Physiology|oesophagus]]
*Chain of fused ganglia running along the floor of the abdomen and thorax
**Nerves are given off from chain
*Complex nervous system
**Well developed visual senses
====Fat Body====
*Large structure
*Cells containing fat vacuoles
*Lines the body cavity and internal organs
*Equivalent to the visceral and parietal peritoneum in mammals
*Food reservoir during hibernation or starvation periods
====Reproductive System====
*Most insects have seperate sexes
*Reproductive organs are analogous to mammals
*Spermatheca present in females
**Accessory female sex organ
**Recepticle for spermatozoa
**Sperm remains viable for most of the female's life cycle
[[Category:Insecta]]
*Covered by an exoskeleton
**Provides support and protection to the living tissues
**Acellular so is secreted by underlying epidermis
**The outer layer is called the '''epicuticle''' which is composed of proteins and covered by a waxy layer
**The inner layers are the '''endocuticle''' and '''exocuticle''' which are composed of protein and chitin
*Body is '''metameric''' (divided into segments)
*Divided into head, body and abdomen
**Articular membranes link segments allowing movement
===Insect Head===
[[Image:Insect Head and eyes.jpg|thumb|right|150px|Alan Hadley]]
[[Image:Insect Eyes.jpg|thumb|right|150px|Alan Hadley]]
[[Image:Blow fly head.jpg|thumb|right|150px|Blowfly Head Close Up - Martin Pot - Wikimedia Commons]]
*Capsule of fused plates at the anterior end of the body
*One large pair of compound eyes
**Honeycomb like corneal facets
*Three simple ocelli
**Dorsal to compound eyes
*One pair of antennae
====Antennae====
*Form varies amongst insecta
**E.g. long and segmented, short and squat etc.
*[[Hair - Anatomy & Physiology|Hairs]] sometimes present
*Aristae (bristles) sometimes present
====Mouthparts====
*Modification depending on feeding method
*Insects which suck up liquified food have an expanded sponge like labellae
**Cannot penetrate skin
**Palps are also present which are sensory structures
*Insects which suck blood have long slender mouthparts for piercing skin
**Hypopharynx
**Mandibles
**Labrum
**Maxillae
*Larval mouthparts are prominent
**One pair of hooks
**Cephalo-pharyngeal skeleton
**Mouthparts help identify larvae
===Insect Thorax===
*Divided into three segments
**Prothorax, mesothorax and metathorax
*Each segment has one pair of legs attached
*One or two pairs of wings may be present on the mesothorax and metathorax
====Leg====
*Leg is attached to the body by '''coxa'''
*Trochanter
*Femur
*Tibia
*Tarsus, which is composed of several segments
*Claw
*Usually six-segmented
====Wing====
[[Image:Insect Wing Venation.jpg|thumb|right|150px|Alan Hadley]]
*Insects usually posess two pairs of wings
*Diptera have a reduced second pair of wings called '''halteres''' for balance
*Membranous outgrowth of the integument
*Strengthened by a network of veins comprising breathing tubes ([[Trachea - Anatomy & Physiology|trachea]]) and [[Vascular System - Anatomy & Physiology|blood vessels]]
*The wing venation can be used for identification
**Longitudinal veins
**Cross veins
**Open cells
**Closed cells
===Insect Abdomen===
*Segmented
*Soft
*Appendages present
**Copulatory claspers
**Ovipositor
**External genitalia
====Respiratory System====
*Branching [[Trachea - Anatomy & Physiology|trachea]] strengthened by spiral thickenings in the walls
*[[Trachea - Anatomy & Physiology|Trachea]] communicate with outside via spiracles
**Spiracles on side of body
**Chitinous openings
**Muscular control so can open and close at will
**Mounted on stigmatic plates
**Lead to trachea
*Muscular contactions of the body wall produce respiratory movements
*Shape of spiracles and stigmatic plates used for species identification
====Alimentary and Excretary System====
*The precise shape of the gut varies between [[:Category:Arthropods|arthropods]]
*The Alimentary canal is divided into fore, mid and hind gut
*Foregut:
**[[Oesophagus - Anatomy & Physiology|Oesophagus]]
**[[Crop- Anatomy and Physiology|Crop]] for temporary food storage
**[[The Proventriculus - Anatomy & Physiology|Proventriculus]]
**[[The Gizzard - Anamtomy & Physiology|Gizzard]] present in insects which eat solid food
***Muscular wall and teeth on inner surface
*Midgut:
**Stores food
**Secretes enzymes for digestion
**Outlet for malpighian tubules (equivalent of the mammalian kidney)
*Hindgut:
**Water resorption
====Circulatory System====
*[[Heart - Anatomy & Physiology|Heart]] situated dorsally
**Valves divide [[Heart - Anatomy & Physiology|heart]] into compartments
**Valves only let blood flow forwards
*[[The Aortic Arches - Anatomy & Physiology|Aorta]]
*Branching [[Vascular System - Anatomy & Physiology|blood vessels]]
*Haemocoele
**General body cavity
**Equivalent to the capillary circulation in mammals
**Contains haemolymph
*Ostia (openings) in the [[Vascular System - Anatomy & Physiology|blood vessel]] walls allow return of blood to the heart
====Nervous System====
*Small brain above the [[Oesophagus - Anatomy & Physiology|oesophagus]]
*Chain of fused ganglia running along the floor of the abdomen and thorax
**Nerves are given off from chain
*Complex nervous system
**Well developed visual senses
====Fat Body====
*Large structure
*Cells containing fat vacuoles
*Lines the body cavity and internal organs
*Equivalent to the visceral and parietal peritoneum in mammals
*Food reservoir during hibernation or starvation periods
====Reproductive System====
*Most insects have seperate sexes
*Reproductive organs are analogous to mammals
*Spermatheca present in females
**Accessory female sex organ
**Recepticle for spermatozoa
**Sperm remains viable for most of the female's life cycle
[[Category:Insecta]]